Teletypewriter switching system



Dec. 7, 1943.

H. R. STARR ET'AL 'I-ELETYPEWRITER SWITCHING SYSTEM 5 Sheets-Sheet l Original Filed June 17,' 1957 ATTORNEY,

H. R. STARR E'r AL TELETYPEWRITER SWITCHING SYSTEM D ec. 7, 1943.

Original Filed June 17, 1937 5 Sheets-Sheet 2,

' H. R. STARR y W. E WADD//VG TON INVENTORS.'

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Dec. 7, 1943. H. R. STARR ETAL 2,336,373

TELETYPEWRITER swITcHING SYSTEM 5 Sheets-Sheet 5 Original Filed June 1'7, 1957 hh mm;

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Dec 7 1943- H. R. sTARR :r1-'AL l TELETYPEWRITER SWITCHING SYSTEM 5 Sheets-Sheet 4 Original Filed June 17, 1957 Patented Dec. 7, 1943 TELETYPEWRITER SWITCHING SYSTEM Harry R. Starr, San Francisco, Calif., and Walter E. Waddington, Franklin Square, N. Y., assignors to American Telephone and Telegraph Company, a corporation of New York Continuation of application 'Serial No. 148,652,

June 17, 1937. Serial No. 340,704

37 Claims.

This invention relates to teletypewriter systems and, more particularly, to an automatic sequential switching teletypewriter system. It is an object and feature of this invention to automatically start and stop the sending mechanisms, such as tape transmitter-distributors, of teletypewriters at subscribers stations connected into a teletypewriter system.

This is a continuation of application Serial No. 148,652, filed June 17, 1937.

It is also an object and feature of this invent-ion, in a teletypewriter system having a. plurality of subscribers teletypewriter stations connected therein, to automatically condition the sending mechanisms, such as tape transmitterdistributors, of the teletypewriter stations in any desired sequence for the transmission of messages.

A further object and feature of this invention is to automatically control the sending mechanisms oi teletypewriters connected into a teletypewriter system, so that, when one teletypewriter stops sending, a preselected teletypewriter will automatically be conditioned for sending and this procedure repeated in any desired sequence.

These objects and features are attained by providing control contacts in the teletypewriters oi a teletypewriter system. These contacts are located in the teletypewriters just above the pull bars and are adapted to be operated by the pull bars when the pull bars are elevated by the reciprocating printing bail of the teletypewriters in response to preassigned permutation code signals. When one of these preassigned permutation code signals is transmitted over the system, it will effect the operation of a Contact in a teletypewriter at each of two different stations. rllhe operation of the contact in one of these teietypewriters will stop the transmitterdistributor of that teletypewriter and the operation of the Contact in the other of the teletypewriters will automatically condition the sending mechanism of that teletypewriter for operation.

rThe operator of this latter teletypewriter will now transmit messages from that teletypewriter for a selected period of time, at the end of which the operator transmits a different preassigned permutation code signal. The transmission of this second code signal operates a contact in the operators teletypewriter to stop his sending f mechanism and also operates a Contact in a teletypewriter at a different station thereby starting the sending mechanism of this teletypewriter. This procedure is repeated until the last teletypewriter in the system has been conditioned This application June 15, 1940,

for sending, after which the last of the preassigned code signals is sent to effect the stopping of the transmitter-distributor in this' teletypewriter together with the starting of the transmitter-distributor in the ilrst'teletypewriter of the system.` The whole procedure is then repeated throughout the duration of the business day thereby permitting a continuous and uninterrupted ilow of transmission regardless of the number of subscribers. It also permits a onemessage rotation system whereby each subscriber may perforate messages in his tape in advance of their transmission and the transmitters will automatically pick up one message from each subscriber in proper rotation or sequence thereby reducing the over-all transmission time.

These and other features of the invention Will be more fully described in connection with the following detailed description of the drawings in which:

Fig. l is a schematic representation of the system as a whole;

Fig. 2 shows the relation of Figs. 3, 4, 5 and 6 and the manner in which they are to be connected;

Fig. 3 illustrates the tape transmitter-distributor at the terminal station shown in Fig. 4, this transmitter-distributor mechanism being typical of that at each of the main subscribers teletype- Writer stations; v

Fig. 4 represents one of the terminal teletypewriter stations of the system having a subsidiary teletypewriter station with means for automatically oonnecting this subsidiary station to the main transmission system;

Fig. 5 shows two intermediate teletypewriter stations in the system; and

Fig. 6- shows another' terminal teletypewriter station of the system having a subsidiary teletypewriter station with means for manually connecting the subsidiary station through the system.

For the purpose of illustration, Fig. 1 has been drawn to illustrate a specific teletypewriter system having terminal stations at New York and Detroit with intermediate stations at Cleveland and Philadelphia, and a subsidiary teletypewriter station at each end of the system connected by a local line to the nearest terminal station. It is to be understood that the specific number and arrangement of stations is shown purely lor illustrative purposes and that the invention is not limited to the number of stations shown nor is it limited to the particular arrangement of the stations shown. I

In Fig. 1, the New York terminal is shown to include a central oice I having a telegraph repeater 2, a switching relay 31, and a plurality of sources of power supply comprising batteries 4, 5, and 9. Connected to central office I is a New York subscribers station 1 having `a teletypewriter 8, a tape transmitter-distributor 9, a switching relay I9, and an auxiliary teletypewriter H. The transmitter-distributor 9 is of the type shown in detail in Fig. 3 and is fully described in Patent 2,055,567, granted September 29, 1939, to E. F. Watson. The disclosure of this Watson patent is incorporated herein by reference as a part of this specification. Also connected to central ofce I is a subsidiary subscribers station I2 having a teletypewriter T1. During business hours, the teletypewriter at the subscribers station 1 is normally connected through repeater 2 at central oiiice I to the main line L, whereas during this period the teletypewriter T1 at station I2 is ordinarily connected by conductor I3 tothe central oihce I, over conductor I4 to the auxiliary teletypewriter II at station 1, and then over conductor I5 to battery 4 ai; central ofce I. Thus, subscribers station I2 is subsidiary to the subscribers station 1 in that it usually `is connected for communication only withthe auX- iliary teletypewriter I I and is not ordinarily connected into the main transmission circuit leading out over line L.

From central oce I, amain transmission path L leads to the intermediate teletypewriter central ofiice I6 at Philadelphia which is provided with telegraph repeaters I1 and I8. Connected to central oiice I6 isa Philadelphia subscribers station I9 which includes a teletypewriter 29 and a tape transmitter-distributor 2I similar to transmitter-distributor 9. After passing through central ofce I5, the main transmission path L leads to the intermediate teletypewriter central omce 22 at Cleveland which is also supplied with two telegraph repeaters 23 and 24. Connected to central oice 22 is a Cleveland subscribers station 25 having a teletypewriter 26 and a tape transmitter-distributor 21 similar to transmitterdistributor 9.

After leaving central ofce 22, the `main transmission path L terminates Vin the terminal teletypewriter central oflce 28 at Detroit. Central ofiice 28 includes the telegraph repeater 29, a switching relay Y39, `and a plurality .of sources of power supply comprising batteries 3l, 32, and 33. Connected to central oice 28 is a Detroit subscribers station 34 having a teletypewriter 35, a tape transmitter-distributor 36 similar to transmitter-distributor 9, manually operable switching keys 31 and 43, and an auxiliary teletypewriter 38. Also connected to central oiiice 28 is a subsidiary subscribers station 39 having a teletypewriter T2. During business hours, teletypewriter 35 at the subscribers station 34 is normally connected through repeater 29 at central oiiice 28 to the main line L, whereas during this period the teletypewriter T2 at station 39 is ordinarily connected by conductor 49 to the central office 2S, over conductor 4I to the auxiliary teletypewriter 38 at station 34, and then over Aconductor 42 to battery 3-I at central office 28. Thus, subscribers station 39 is subsidiary to subscribers .station 34 in that it usually is connected forcommunication only with the auxiliary teletypewriter 38 and is not ordinarily connected into the main transmission circuit leading out over line L.

In this particular embodiment of the .inventransmitter-distributor 2 I.

tion, the subscribers stations 1, I9, 25, and 34 are ordinarily connected to each other through their respective central offices I, I6, 22, and 28 during business hours. The operation of the system is then begun by the subscriber at one station, lsuch as 'the New York station 1, transmitting a message, or series of messages, out over the main transmission line L to each of the other subscribers stations I9, 25, and 34 by means of the transmitter-distributor 9. This message, cr series of messages, will be recorded on each of the teletypewriters 8, 20, 26, and 35. The termination of transmission from station 8 may be determined arbitrarily by the subscriber, such as by transmitting all the messages that happen at that time to be perforated on the tape of the transmitter-distributor 9. However, in a busy system, it may be found to be more enicient to limit the sending period either to just one message at a time or to a definite preassigned interval of time, such as two minutes.

In either event, the subscriber terminates his transmission with a preassigned character, such as upper case H. The transmission of the permutation code signal for upper case H operates selecting mechanism in the teletypewriter 8 (shown in detail in Fig. Li) which effects the momentary operation of a special Contact 64 (Fig. 4) in teletypewriter 8 which, in turn, effects the stopping of the subscribers transmitterdistributor 9. This uppercase H signal is received by teletypewriters 29, 26, and 35 and operates mechanism in the teletypewriter 29 which eiiects the-operation of a contact which, in turn, effects the starting of the transmitter-distributor 2I at station I9 in a manner which will be more fully described hereinafter.

The subscriber at the Philadelphia station I9 now transmits messages out over line L which will lbe recorded on each of the teletypewriters 8, 29, 25, and 35. At the end of his transmission Iperiod, the subscriber at station I9 transmits a particular preassigned permutation code signal, such as upper case J. When this permutation code signal passes through teletypewriter l29, it actuates selecting mechanism in teletypewriter to effect the momentary operation of a special contact (Fig. 5) in teletypewriter 20 which, in turn, Veiects the stopping of the subscribers This upper case J code signal is received by teletypewriters 9, 26, and 35 and operates mechanism in teletypewriter V26 which effects the operation of a contact which, in turn, effects the starting of the trans- Amitter-distributor 21 at station 25 in a manner that will be described hereinafter.

The subscriber at the Cleveland station now transmits messages out over line L which will be recorded by each of the teletypewriters 8, 2l), 2B and35. At the end of his transmission period, the subscriber at station 25 transmits a particular preassigned permutation code signal, such as upper case G, which momentarily operates a contact in the teletypewriter 25 and a contact in the teletypewriter 35. The operation of the former contact effects the stopping of the transmitter-distributor 21 and the operation of the latter contactefects the starting of transmitterdistributor 36 as will be described in more detail hereinafter.

The subscriber at the Detroit station 34 now ytakes his turn at transmitting messages out over Vtransmission period, the subscriber at station 34 will transmit a diierent preassigned permutation code signal, such as upper case M, which momentarily operates the contact in each of teletypewriters 8 and 35. The operation of the contact in teletypewriter S5 effects the stopping of the transmitter-distributor 38 while the operation of the contact in teletypewriter S effects the starting of transmitter-distributor 9 as wili be explained hereinafter.

The subscriber at the New York station i now takes another turn at transmitting messages out over line L to be recorded by teletypewriters 8, 29, 26, and 35. At the end or" his transmission period, the subscriber at station l again transmits the particular permutation code signal, H, which has been assigned to stop his transmitter-distributor 9 and to start the transmitter-distributor 2l at the next station i9 in the sequence of the circuit. The procedure of operation described above is repeated for the duration of business hours with each subscriber closing his transmis-v sion period by transmitting a particular preassigned permutation code signal designed to stop his transmitter-distributor and to start the next transmitter-distributor in the sequence of the circuit.

A preferred method of operating this circuit is for each subscriber to perforate a length of tape which will reduire two minutes to transmit and to end this section of tape with the code characil ter assigned to that subscribers station. The subscriber can then perforate another two-minute section of tape and end it with the same code character and so on throughout the business day. This renders the operation of the system l* more automatic as the transmitter-distributors will be automatically started and stopped. It also permits a higher rate of speed in transmitting because, since the tape is perforated in advance, there will be no delays, such as would otherwise be caused by an operator in the ordinary method of perlorating tape for immediate transmission. This method of operation also gives each subscriber an equal amount of line time for transmission and reduces transmission time in that it does not reduire the usual call and go ahead signals. The same results can be obtained by perforating a switching signal at the end of each message instead of at the end ci each two-minute section.

In the event that one subscriber had no message to transmit during a certain portion oi the business day, that subscriber would periorate in his transmitting tape a succession of perforations i .f

corresponding to a series of the code character assigned to his station. Then, whenever his transmitter-distributor should be started, it would merely transmit one of these code characters which would immediately stop his transmiter-distributcr and start the next transmitterdistributor. in this way, the full line time would be more efficiently utilized without departing from the automatic and sequential method of starting and stopping each subscribers transmitter-distributor. It is to be understood that the invention is not limited to this preferred embodiment but that the sequence and time of transmission may be varied as desired.

At the Detroit end of the system is a subsidiary subscribers station 99 connected to the central oce 28 by a local line G9. Normally, station 99 is connected by conductors Si and t2 to an auxiliary teletypewriter 98 at station Sil and .to battery 3l at central office 2e. The subscriber at station 34 can communicate with the subscriber at station 39 by means of the auxiliary teletypewriter 38. In the event that the operator at station 39 wishes to connect his teletypewriter T2 to the main transmission line L for reception or transmission of messages, he can record this desire on the auxiliary teletypewriter 38 at station 34.

In response to this request, the subscriber at station 34 manually operates key 31 momentarily. The operation of key 3l applies ground from key i3 to the switching relay 30 at central ofiice 28 thereby closing a path for battery S3 to energize relay 3Q. Upon being energized, relay 3il operates its armatures and locks-up through its left armature to the ground on key 43. At the same time, the inner right armature of relay 30 is operated and switches conductor [i2 from battery 3i to the joining conductor 44 while the outer right armature switches conductor` i5 from battery 32 to the joining conductor M and thence to conductor 42. This switching operation serves to switch station 39 into the main transmission line L or, in other words, the main transmission L is extended to station 99.

The subscriber at station 3d can restore the system to its normal condition at any time by manually operating key 43 momentarily. The opening of key 43 opens the locking-up circuit of relay 3B by removing the ground on key 43. When the locking-up circuit is opened relay 39 will release its armatures thereby switching conductor l2 to battery 3i and conductor i5 to battery 32. Thus, it can be seen that station 99 is subsidiary to station 34 because it is normally connected for transmission with the auxiliary teletypewriter 33 and can be connected into, or disconnected from the main transmission line L only when the subscriber at station 34 operates key 31 or key 43.

At the New York end of the system is another subsidiary subscribers station l2 connected to central oice l by a local line i9. Normally, station i2 is connected by conductors i4 and l5 to an auxiliary teletvpewriter il at station 'I and to battery 4 at central office i. The subscriber at station 1 can communicate with the subscriber at station l2 by means of the auxiliary teletypewriter Il.

If it is desired to connect the subsidiary subscribers teletypewriter T1 to themain transmission line L, this can be eiected by the transmission by the subscriber at station l, or by any of the other subscribers at the other connected stations, of a preassigned permutation code signal, such as upper case A, over the line L for reception by all of the connected teletypewriters. However, the teletypewriter 8 at station 'l is the only teletypewriter which is adapted to make particular use of this signal because teletypewriter 8 is provided with a special contact 4t which is adapted to be momentarily'operated by the selecting mechanism in teletypewriter 8 in response to the reception by teletypewriter 3 of upper case A.

When contact 46 is momentarily closed in response to the reception of upper case A, it closes a path for energizing the control relay i9 which operates its armatures and locks-up over a path through its left armature and Contact il?. The operation of the right armature of relay I@ closes a path for enabling battery ii to .energize switching relay 3 which operates its armatures and remains energized as long as relay I9 holds its right armature;,operatedL Theyoperation of; the inner armature of.' relay 3 s witcheszconductor l5., from battery 4 to the joining conductor l48u/bile, at the jsame time, the outer armature of relay 3 switchesconductor 55 from r'battery 5to the joining conductor k48 and` thence to conductor l5, lThis .switching operation serves to switch station l2 into the main transmission line L, or in other words ,the 4main transmission line L is extended tostation l2.A

Whenever desired, station l2 can bedisconnected from` line L andthe system restored to normal by the transmissionL or another v.preassigned permutation codesignal, such as upper case S. This particularsignal may be sent from any of the teletypewriters 8 20, 2S, 3 5, or I. I tmay alsobe sent from -teletypewriter T2 if this teletypewriter happens to be connected into lineL at this time. Regardless of what gteletypewriter the signal is transmitted from, itis received by teletypewriter 8 whereit lactuates selecting mechanism .to eifect themomentary operation of vcontact 41. The opening of contact 41 serves tocpen the locking-up circuit of control relay I0, which,

consequently, releases its-armatures. The release of the right armatureof relay I0 opens the energizing circuit of switching relay 3 with the result tha-t relay 3 releases its armatures thereby switching conductor I5 to battery 4 and conductory 5 5 .to battery 5. This switching actiondisconnects station l 2 from line` L and leaves station I2 in its local circuit through the auxiliary teletypewriter l l. From this description it is evident that station l2 is subsidiary in its nature because it can be connected into or disconnectedfromthe main transmission line L only by the operation of contacts at station 9.

It is -tc be understood that two different systems, one a mechanical system and the other a manual system, have been shown for switching the two subsidiary stations I2v and 39 for purposes of illustrating the wide scope of the invention which is not limited to the specic arrangements shown and is also notflimited to only two subsidiary stations; The invention is flexible in that it may be varied to -meet the requirements of different circuit installations. Thus, `by means of this invention, transmitter-distributors at a plurality of subscribers stations can be automatically started and stopped in any desired sequence and subsidiary teletypewriter stations may be automatically switched into, or disconnected from, a teletypewriter circuit, or communication line, at another station.

As was stated above, Fig; 2` shows the relation of Figs. 3,4, '5, and 6 and the manner, in which they are to be connected. Fig. '3 illustrates the tape transmitter-distributor 9 which is employed at the New York subscribers station 1 and which is typical of that used at each of the main subscribers stations; This transmitter-distributor is similar to that disclosed anddescribed in the 'aforementioned Watson Patent y2;O55567, except vkthat the transmitter-distributor lshown in this Watson patent is adapted for use in transmitting a six-unit permutation code, whereas the transmitter-distributor 9 in Fig. 3 is designed to transmit a five-unit code. Watsons six-unit transmitterdistributor can be readily converted to a veunit transmitter-distributor by substituting a distributor face-plate 58 having a transmitting seg- -m'ented ring with seven segments insead of the eight segments shown inthe Watson patent and byremoving one of the contact levers with its contact toneuaset of. spacnaand marking 9011- tacts. and. associated conductors.

To initiate transmission, the subscriberatstation 1 closeshis manually operable vswitches 68 and 69 to start histeletypewriter motor 10 and the motor 1l of the transmitter-distribuor 9.

Before operating the transmitter-distributor 9,

the subscriber at station 9 rst perforates permutation code combinations in his transmitting tape by means of his perforator which may be of vsegmented ring 53 of the distributor face-plate 58. The circuit for transmitting the permutation code signals from transmitter-distributor 9 leads from battery 5 over conductor .55, overthe rings of the distributor face-plate 58, conductor 54, teletypewriter 8, break key |86 (Fig. 4), sending contacts 56, receiving magnet 51, centraloiiice telegraph repeater 2, and then out over line L to the next central oflice I6.

The teletypewriter 8 is shown to be provided with three sets of contacts 46, 41, and 59 mounted in teletypewriter 8 on a plate 66. It can be seen in the drawings that contacts 46 and 59 are normally open while contact 41 is normally closed and that the contacts 46, 41, and 59 are located over the tops of pull bars 6I, 62, and 63, respectively. Teletypewriter 8 is also provided with a normally closed contact 64, which is operable by a system of levers, a normally open contact 65, operable by the platen assembly 66, and another normally closed contact 61, operable by a particular arrangement of the teletypewriter mechanism. Since the main transmission circuit L has already been set up by the operators at the various central ol'ices in the system, the subscriber at station 1 is now in a position to initiate transmission. This he does by rst transmitting from his teletypewriter 8 the permutation code combination for figures This code combination is known as the upper case signal because it operates the selecting mechanism V12 to effect the selection and operation of the iigures pull bar 13. Elevation of pull bar 13 by the reciprocating bail 14 elevates extension 15 of pull bar 13 thereby tilting bell crank 16 which releases catch 11 to allow spring 18 to pull the platen assembly 66 forward into its upper case position. In moving forward, the platen assembly 66 carries latch .11 forward along the edge of bell crank 16 thereby forcing downward the right end of bell crank 16 to close the platen contact 65 which remains closed during the entire time that platen 89 remains in its upper case position.

The subscriber then operates his teletypewriter 8 to transmit an M code combination lsignal which operates his selecting mechanism 12 to select pull bar 63 for operation by bail 14. The momentary. elevation of pull bar 63 serves to momentarily close contact 59 thereby closing a path for positive current to pass from the positive terminal of the local source of direct current over conductor 90, through the winding of relay 9|, over contact59 (now closed), conductor 92, over contact `65 (now closed), and4 then along conductor 93 to the negative terminal of the local source of power supply. In response to the closing of this circuit, relay Si becomes energized and operates its armatures and locks-up over a path through its left armature, along conductor 94, through the normally closed contact SQ, conductor 95, through the normally closed break Contact 8l, conductor so, and then along conductor 93 to the negative terminal of the local source of power supply.

At the same time, the right armature of relay 9i opens the energizing circuit of relay 91 which, accordingly, releases its armature. The release of the armature or relay Sl closes a circuit leading from the positive power terminal along conductor Q, over the armature of relay Si, conductor $38, through the winding of Stop magnet 9S (Fig. 3), conductor l, over the tape tension contact lill, conductor HG2, and `then along conductor 93 to the negative power terminal. rhis serves to energize control magnet Q9 which opera-tes the stop arm its about its pivot EM to move the let end of stop arm i533 out of engagement with the shoulder lil formed by the periphery of the stop cani H35 mounted on the main drive shaft E05. lThis allows the friction clutch lil? to effect continuous rotation of the distributor brush arm Hi8 for the transmission of signals by the transmitter-distributor 9 out over conductors iid and 55.

This condition continues until either contact S or 6l is operated by a code signal or until the tape tension contact lill is operated by the stop lever lili-l in the manner described in the Watson patent to eiect the opening of the energizing circuit of magnet 99. Should this occur, then magnet 99 would release the stop arm H33 which would then be pulled around its pivot lii by the spring HS and would engage with the shoulder lli of the stop cam 85. This would stop shaft it and brush arm Hi8 from rotating and would disengage the friction clutch lill. However, ii it be assumed that none of these contacts are now operated, then the subscriber at station l will be able to transmit messages from his transmitter-distributor il out over line L to the connected teletypewriters 2Q, 26, and for the full length of his transmission time. Due to the tact that the contacts 4F, M, 5d, and 521 in his teletypewriter 8 are eiective for performing their special switching function only when the platen assembly Et is in its upper case position, the subscriber at station 'l may use the lower case code combinations for operating the pull bars Ei, 3, and l@ for performing their ordinary printing functions.

After the subscriber at station l has used his ull transmission time, he concludes his transmission with the permutation code combination for gures followed by the code combination for Il As was described above, the iigures signal is known as the upper case signal because the reception of this signal causes selecting mechanism 12 in each of the connected teletypewriters in the system to eiect the Selection and operation of their figures pull bar corresponding to pull bar i3 in teletypewriter 8. As was also described above, elevation of bar '13, by the printing bail la, clevates extension l of pull bar l thereby tilting ball crank lli which releases latch il to allow spring lil to pull the platen assembly forward into its upper case position.

The reception or the code combination causes the selecting mechanism 'l2 to effect the operation of pull bar 7B which, by means of the rack and pinion gears Sli and 8l move the type bar 82 downward in an arcuate path. Projection $3 on bar 82 will consequently strike lever Bil, pivotally attached to the platen assembly lit, thereby driving downward the right end of lever Se. This causes the top end oi lever 85 to move to the right to allow spring to pull down the right end o lever 3l into latching engagement with the top end of lever 85. At the same time, the left end of lever Sl is driven upward to open the normally closed contact However, this opening of contact Eil is only momentary because the reciprocating bail 'E4 soon comes down and forces down the left e'nd of lever B'i thereby allowing contact i to close and, at the same time, forcing the right end oi lever 8l upward to allow spring t5 to puli lever 85 back into its normal position.

In this connection, it should be noted that this system of levers can only be operated by an upper case l-l signal because, when a lower case H signal is received, the platen assembly 6% is back in its lower case position so that the projection 83 of bar 82 would not then be able to hit against lever 8f3 due to lever E@ being pulled back with the platen assembly E@ to which it is attached. Consequently, the circuit to contact need not pass through the platen contact 55.

rEhe momentary operation of contact dit serves to open the locking-up circuit for relay @i which, accordingly, releases its armatures. The right armature of relay 9! now closes the energizingcircuit for relay @l which operates its armature thereby opening the energizing path or magnet S9 over conductors 9d, 9S, itil, and EQ2. Consequently, magnet QQ releases the stop arm m3 and allows spring l le to pullstop arm it around its pivot lil-"sier engaging with shoulder lli of the stop cam mii. This stops shaft iil and brush arm itil from rotating and disengages the friction clutch itl. Motor il now runs idle and no transmission can be eiected by transmitterdistributor 9 until the energizing circuit for magnet B9 is again closed.y

At the same time, the l-l code signal combination is transmitted out over line L to the other connected teletypewriters 2li, 26, and 35 where it causes their selecting mechanism, similar to selecting mechanism 'i2 in teletypewriter 8, to effect the operation of a pull bar, similar to pull bar l. In the teletypewriter 29 at the Philadelphia subscribers station I9 (Fig. 5), the operation or" this pu1l bar effects the operation of a type bar, similar to type bar 82, which, in turn, operates a system of levers, similar to levers Sri, ilo, and 3l'. This results in the momentary operation of a contact H2 which is similar to contact til except that contact H2 is the reverse of contact Sli in that it is normally open and is so designed that the upward thrust of the lever in teletypewriter 2u which corresponds to lever Sl in teletypewriter 8 will momentarily close contact H2. Y

The closing of contacti i2 closes a circuit leading from Ithe positive terminal of the local source of power supply, along conductor lill, through the winding of relay H5, contact H2, conductor lle, conducto-r 133, conductorl lil, normally closed break contact H8, conductordl, conductor itil, and then over conductor lli to the negative terminal of the local source of power supply. Consequently, relay H5 operates its armatures and locks-up over a circuit traced from its inner armature and along conductor' l22- to junction 31. Here the locking-up path divides into ,two paths, one pata leading over "conque"- to "|32, nbally 'closed "Contact |29, `c`ldutor |33, "conductor 1, break contact |18, conductor ne, conductor -`|20, and nien"over conductor ;|2 to theheg'ative 'terminal of the local "source of power supply.

The other 'path leads from Ajunction 13|, and over conductor |34 to the normally'closed platen contact 'I,I3. This platen contact |,I3 is the reverse of the 'platen `contact 65 in Fig. 4; in that it "s 'normally Closed. v't this partcllIu' Ambment,'cont act`| I3 isopien due tothe'tr'ansmission and reception of 'the gures signal, However, as 'soon as 'a letters signal is transmitted, the platen '.(l'l'O't shfoivh) in teletypewriter 20 'Will be shiftedtoiitslowercaseposition to'close'a branch of the locking-:lip path 'from conductor `|`34,"0ver contact I|3, conductor |23, conductor I|1,`brea'k contact I I8, vconductor TIB, :conductor |20, and

tnenovercoriduetor |2| "to the"negative termrnal of thelocalsurce'of power supply.

At `'the v"same time, the' outer armature jef Vrelay opens vthe `energizing circuit of relay |24 which, accordingly, releases its armaturfeto close a path from tli'e positive terminal 'of 'the 'local source; of power'supply' over conductor: I'I 1|, `armature `of re1a`y |24, along Y't:'f mduetor |25 'to the transmitter-distributor 2|, through'the winding of magnet '|26 whichis'similar-to magnet L99 in Fig. l3, tape tension'cont'act fil-1 which is similar to contact IOI in FguByconductor I28, con'd'uc tor AI 20,'an`dthenl long' conductor I2 I `Ato the negative terminal ofthe'loeal source of powensupply. Theenergizationof'magnet I26jeifects the operation of astoparm (not shown) which is similar to stop arm :|03 'in the transmitter-'distributor 9 and which Der'formsthe-same function in transmitterfdistributcr 2| that stop arm |03 does in`transmitter-distributor 9. 'I hsfconditions the transmitterdistributor 2 I "at Vthe Philadelphia subscrib'e'rs station I 9 `for 'th'e'ta'nsm'issic-n lof'messages out over linelq. e

The A'locking-"up circuit :for "relay I'I 5 Vwill remain closed until a figuresfsi'gnalis `s'e'ntiiollowed by a J signalbecausa 'although `a frigur'esl signal would -oipezn 'conta`ct 3, the other side'of the locking-up circuit'wouldfremainv closed thro-ugh'the J Contact |29. `VS/'henthe platen is'in it`s lowercasepositin, 'opening or lthefJ contact 29jwou1don1y open'one 'branch ofthe locking-up *circuit 'because the other branch wouldbeiclose'd through contact ||3. v n

After 'the-subscriber 'at Vstation I9 `Itas' used 'his full transmissiontime, he concludes his transmission period `4by transmitting v'the permutation code combination for iiguresf which opens "the locking-'up *path *through contact I |13, followed by the codejc'onibination'for J." This J signal actuatesthe selecting vmechanism of the subscribers "teletypewriter thY- efle'ct `theoperation of a Vpull bar whichinonientarily opens 'the n ormally closed-contact|29 `which is similar'to vthe pull bar contact 41v (Fig. 4) except thatit islocated over the topjof the J-pull lbarin"t'eletype Writer20 insteadof the Mpulll bar.

When contact ?|29'ope ns,jit opensits Vbranch of thellocking-u'p'circutfandj-since v4both branches of vthe `locking-up circuit are now both open Y at the same Vtinie, Arelay I I5will-bfc`me d eener'gized and will release itsfai'niaturs thereby closingthe energizing circuit, of -relay |24. Relay |24 now operates its armatureto open the energizing circuit ove'r 'conductor |125t`o magnet `|21; ly'vhich-releases its @associated "stop farm (gnot shown) j for engagement "with theshldr l'of tlieiston `Vcam (not shown) jin "the transmitter-distributor 2|. Brushar'n `|30 will now be prevented from vfurther rotation and no transmission can be effected by`transmitter-distributor 2| until magnet |25 isa'gain energized.

At the same time, the J codesignal-combination'is transmitted out over line L to the other connected "t'eletypewriters 26, 35, and which have already moved their platen assemblies into theirup'percase positionsvin response to the iigu'res"` signal which preceded-the J signal. In the 'teletypewriter `2S Vat the Cleveland subscribers station 25, thenormally open `platen Contact |35, which is-similar'to the platen contacti65 shown in Fig.j4, i'sclosedin response to the reception of the gures signal. When the J signal is received by fteletypewriter 25, it causes dthe selecting mechanism in teletypewriter 26 Avto select Yth'je 'J pull bar for operation by thebairof teletypewriter 26. In operating, the 'J"pull bar closes the J Contact |36 thereby completing an energizing circuit for relay |31 fromthe 'positivelterminal of the local source of power supply, 'over 'conductor 33, resistance |59, throughthe winding of relay |31, over Contact |36, conductor |39, through the v'platen contact |`35 (now closed), conductorl40, and then along conductor '14| to 'the negative terminal of the local source of power supply.

This serves to energize `relay|31 which operates both'its armatures and locks-up overits inner armature, conductor |42, normally closed break contact 143,'c'ofn`c1uctor |40, and then over conductor |41 Yto 'the negative terminal of the local source of^`powersupply. The 'outerarmature oi relay u|31 lopens the energizingcircuit for relay |44 which, accordingly, 'releases its armature to close "an energizing `vcircuit over conductor |45 to"transmitter-distributor 21,"through the windin`g`,` f"`1'ra'g'n'et |46 which is similar to magnet@ i'n Fg."3, tapei'thsion Contact T41, conductor |23, coii'cictr T40, rid'tlnover conductor |4| to th'e "ngative "terminal 'of the local source of pow''r kvsupply. The enrgiation "of magnet |616 eifects'the 'operation `f`a 's'tp arm (not shown) which is similar to stop-am |03 in the transmitter-distributor u9 in Fig. 3 -and which perfrinsthe'sahie function in transmitter-distributo'r 2 I 'thatstop arm I03` performs'in transmitterdistributor V`conditions the apparatus at the'v Cleveland vsubscribers station Yfor the transmission-oi messages out over line L.

Wh'en theCleveland subscriber at station 25 concludes his transmitting period, he finishes his transmission Witha permutation code combination for guresr followediby the code combination for "G. The iigures 'signal yeffects the closing of theplatencontact |35 andthe G signareectstheoperation of apull barfin teletypewriter 26 Whichmomentarily closes the normally Aopen-contact y|49 thereby closing a path for vshunting Amagnet |31. Thisshunt'path leads fromthe positive `tenninal 'of .thelocal vsource of power supply, along conductor |38, Vthrough .resis'tances |501and |5|, conductor 152, Contact |49,'conductor I'39,`conta'ct |35, conductor |40, andith'en overc'onductor T Il'I to the negative"- terminal of theV local source for? power supply.

`The value offtheresistance F51 is small and is designed' to4 be vsufficiently-less than-theresistance of relay |31 so that the closing of the circuit tliroiglitlie`fG'Contact |49 will effectively shunt relay F31 "'w'hih will YFthen release' its" armatures. The 'releaseftheinnramature of relay `I3-1 will open the locking-up circuit of relay |31 and the release of the outer armature will close the circuit for energizing relay |44. Relay |44 will now operate its armature to open the circuit for energizing magnet |46 which releases its associated stop arm (not shown) for engagement with the shoulder or the stop cam (not shown) in the transmitter-distributor 21 thereby holding brush arm |53 from further rotation at this time. No transmission of messages can now be effected by the transmitter-distributor 21 at station 25 until magnet |45 is again energized by the release of the armature of relay |44.

This figures signal is received by the teletypewriter 35 at the Detroit subscribers station 34 where it effects the closing of a platen contact |54 similar to the platen contact 65 in teletypewriter in Fig. 4. The G code signal causes the selecting mechanism of the teletypewriter 35 to select the G pull bar which is elevated by the reciprocating bail of teletypewriter 35 to close contact |55. The closure of these two contacts closes a path for energizing relay |56 from the positive terminal of the local source of power supply, along conductor |51, through the winding of relay |55, conductor |58, over contact |55, conductor |59, platen contact |54, conductor |613, and then along conductor IBI to the negative terminal of the local source of power SUDDy- Relay |56 now operates its armatures and locks-up over a path traced from the positive terminal of the local source of power supply, over conductor |51, through the winding of relay |56, conductor |52, through the normally closed break contact |53, conductor |64, over the non-operated armature of relay |55, operated left armature of relay |55, and then along conductor |61 to the negative terminal of the local source of power supply. At the same time, the right armature of relay |56 is operated to open the energizing circuit of relay |66, which accordingly releases its armature to close an energizing circuit over conductor |51 to transmitter-distributor 35, through the winding of control magnet |68 which is similar to magnet 59 in Fig. 3, tape tension contact |69, conductor |113, conductor l, and then along conductor ll to the negative terminal of the local source of power supply. The energization of magnet |68 effects the operation of a stop arm (not shown) which is similar to stop arm |53 in the transmitter-distributor 9 in Fig. 3 and which performs the same function in transmitter-distributor 36 that stop arm |03 performs in transmitter-distributor 9. This conditions the apparatus at the Detroit subscribers station for the transmission of messages out over line L.

When the Detroit subscriber at station 34 concludes his transmitting period, he nishes his transmission with a permutation code combination for figures followed by the code combination for M The figures signal effects the closing of a platen contact |54 and the M signal effects the operation of a pull bar in teletypewriter 35 which momentarily closes the normally open contact |1| thereby closing a path for energizing relay |55 from the positive terminal ofthe local source of power supply through the winding of relay |55, conductor |12, contact I1 I, conductor |55, platen contact 54, conductor |65, and then along conductor |6I, to the negative terminal of the local source of power supply. v

Upon being energized, relay |65 operates its armature which opens the locking-up circuit of relay |55 which, accordingly, releases both its armatures. The release of the left armature of relay |56 will completely open the locking-up circuit of relay |56 and the release of the right armature will close the circuit for energizing relay ltt. Relay |65 will now operate its armature to open the circuit for energizing magnet |53 which thereupon releases its associated stop arm (not shown) for engagement with the shoulder of the stop cam (not shown) in the transmitterdistributor 35 thereby holding brush arm llt from further rotation at this time. No transmission of messages can now be effected by the transmitter-distributor 36 until magnet it is again energized by the release o-f the armature of relay |66.

The figures signal is received by the teletypewriter 8 at the New York subscribers station 1 where it effects the Closing of the platen contact S5 in the manner described above. The M code signal causes the selecting mechanism 12 of teletypewriter 8 to select the M pull bar G3 which is thereupon elevated by the reciprocating bail 14 and closes the M contact 5e momentarily. The closure of contacts 59 and G5 completes a circuit for energizing relay 9| over a path traced from the positive terminal of the local power supply source, along conductor et, through the winding of relay 9|, .contact 55, conductor 92, contact 65, and then along conductor 93, to the negative terminal of the local source of power supply.

Upon being energized, relay 9| operates both its armatures and locks-up over its left armature along conductor 94, through the normally closed Contact 54, conductor 95, over the normally closed break contact 61, conductor 93, and then along conductor Q3 to the negative terminal of the local source of power supply. The right armature of relay Si, upon being operated, opens the energizing circuit for relay 91 which thereupon releases its armature to close a circuit traced from the positive terminal of the local power supply source along conductor 55, over the armature of relay 91, along conductor QS to the transmitter-distributor 8, magnet 99, conductor itil, tape tension contact lill, conductor |532, and then along conductor Q3 to the negative terminal of the local source of power supply. As was described above, the energization of magnet 99 eects the operation of a stop arm |53 and swings it about its pivot ||4 to remove it from locking engagement with shoulder of the stop cam |55. Friction clutch |01 is now able to eect the rotation of drive shaft |66 and brush arm |08 thereby conditioning the transmitter-distributor 9 for the transmission of messages out over line L.

At the termination of his transmission, eriod, the subscriber at the New York station l concludes his transmission with the permutation.

code combination for"figures and The transmission of these two signals effects the op eration of contacts 64 and ||2 (Fig. 5) thereby stopping transmitter-distributor 9 and starting transmitter-distributor 2| in the manner described above. The operating sequence described above is then repeated throughout the durationL of the business day.

Connected to the Detroit central office 23 is a subsidiary subscribers station 39 having a teletypewriter T2 which, as was described above, is connected during business hours through central oice V28 to the auXiliary-teletypewriter 38 fat .the Detroit subscribervs station '34. Whenever lit -is desired to connect teletypewriterTz vinto the main transmission line L, 'thesubscriberat theDetrOit subscriber-s station 34 manuallyclcses his normally open key 31 momentarily thereby closinga circuit for energizing the'switching relay Bilffrom battery33. -Relay 30 now operates its armatures and locks-up through `its left armature. `At the same time, the inner right Aarmature of relayv3 is'operated'and switches-conductor42 from battery13I v'to the -joining conductor 44, while the outer armature of relay 36 switches conductor 45 from Ybattery 32 itc-the joining conductor `44 and thenceto-conductor 42. lThis switching operation serves toswitch station -39into the main transmission 4line L or,in other words, the main transmission line L is extended to station-38.

-As was describedabove,lthe subscriber atestation-34 can restore-thesystem to its normal con dition at any timeby'manuallyopenin'grthe Inormally closed Ykey 43 momentarily to Vopen the locking-up circuit-of-relay. lRelay iwill now release its armatures thereby lsWi-tching 4conductor 42 to battery3I and `conductor-45 tolbattery 32.

A-similar Vsubsidiary subs'cribers station I21is connected vtof-the New York centralfofiice-l-by a lccal line L3 and-is normally connectedrby-ccnductors I 4 and I5 lto an auxiliary Yteletypewriter Il at stationJ-and tobattery 4 atfcentral oicel.

The subscriber at the New Yorksubscribers station 1 can connect teletypewriter Ti at station I2 into the main transmission -line L Vby manuallyclosing the normally open key 414 `momentarily. Thisclosesapath from the positive terminal of the loc-al source -of power supply, along `conductor 9i), through vthe winding of control relay vIt), contact -IA-14, over the normally closed key |15, conductor |16, normally -closed contact 41, and thenalong 'conductor I11to the negative terminal of lthe/-localsource cf power supply. Relay I now operates `its armatures, andlocks-upover its left armaturegthrough key 115, conductor I'6,'normally'closed contact 41, and then along conductor -If11 4to the negative terminal of the local source of power supply.

At the same time,theright armature-ofrentrol relay IG closes a path forenabling-current from battery to pass through and energize switching relay 3 which remains energized 'as long las, relay Il) remains energized. Relay -3 now operates its armatures; Athe inner armature switches conductor -I Sironi battery 4 to the'joining vconductor 48 and the outer armature switches conductor 55 from battery 5 to the joining conductor 48 and thence to conductor I5. This switchingvoperaticn 'serves to switch station I2 into the main transmission line L, orin other words, the main transmission line lL is extended to station I2.

The subscriber at the New York subscribers station 1 can disconnect -theteletypewriter T1 at station l2 from the 'main-transmission line /L at any time by momentarilyopening 'thenormally closed -key |13 which opens'the locking-up circuit of'relay I0 which thereupon releases its armature-to'open the energizing circuit ofthe switching relay3. Relay-3 now releases its armatures thereby switchingY conductor i5 'to battery'.-

@essere nected subscribers" stations, .including the subscriberf-at the New `Ecforks'tation 11, 'can vconnect the teletypewriter T1 at 'station I2 into Athe main transmission Aline L .by transmitting vthe Ycode combinations lfor gures`and fAJ .This closes the 'platen Vcontact L65 in the ,-'manner .described above .and .also actuates the selecting mechanism1-2 tofeie'ct the elevation of `pull bar A6I by bail 14, thereby closing contact 46 momentarily. The iclosing of fthese .two contacts `closes .a path for energizing ..relay -IJJ from 'the .negative terminal of .thelocal source of power supply, over conductor 90, .through .the winding of relay I0, contact 46, conductor 92, platen contact 55, and then .along .conductor 93 .to .the negative terminal of .theflocal source of 'power.supply. This causes relay l0 to operate its :armatures 'and vto lock-up over la 4path :from `its operated .left armature, through lthe .normally closed Contact |15, conductor 1:16, normallyclosed contact 41, and then along conductor II1 to thenegative terminal of the local ksource-:of ,power supply. .The operation of .theriglfit'armature vof relay .-I) closes vthe energizingcircuit forrelay .3 `which switches the teletypewriter T1 tinto the 'main transmissiony line L. in `the 4manner described above.

Whenever desired, any of the-connected subscribers, including `the subscriber at the subsidiary `station =I2, canswitch the teletypewriter T1 from the main line L back into its local Acircuit by transmitting a figures signal followed by an S signal. The figures signal eiectsthe closing of the :platen contact ,and the S signal effects the operation of dpull bar `62 which opens momentarily the normally closed contact 41 vthereby opening the .locking-up circuit of relay I0. vRelay l0 vnow releases-its armatures thus opening `the energizing `circuit of relay 3 which also releases its armatures "to switch teletypewriter Ti back into its local circuit.

It-will .be noted that the.V platen contact 65 is not connected intcthe-locking-up circuit through contact 41. This is because ,teletypewritera is of the type .disclosedinPatent 1,904,164fgranted April 18,:1933, to S. VMorton Yet-al. and, in teletypewriters of this type, the pull bar 62 is operated in response Atoan S signali only when the platen 89 -is in itsiupper case position. Pull bar 62 lis known as the bell pull bar because and conductor 55 to battery-'5. This-'switching action disconnects station I-2 from llineL and leaves station Y I 2 in -its'local -circuitthrough-the auxiliary l teletypewriter TI I ordinarily,in teletypewriters of this type, its operation eiectsvthe ringing of a signal ybell in the teletypewriter to attract the attention of the teletypewriter attendant. The mechanism for restricting the .operation of..pull kbar 62 to an f upper case signal includes a sixth selecting vane and'is fully described in the Morton et al patent, the disclosure of this patent being `hereby incorporated herein by referencaas-apar-t offthis specication. Thereforesince .contact 41 can only be closed when platen 89 is in itsupper case position, this leaves the'lower case S signal'free tov perform its ordinary printing function.

lInfa'ct, it"'should'be noted thatall of the code operatedcontacts can be operated only when the platen 89'ofeach'teletypewriter isin its upper case position. This prevents "unnecessary interference VWiththe 'ordinary A.printing functions of the pull -bars andr their `associated type'ba'rs becauseall the pull bars Vare free* to performtheir ordinarynprinting functions. `In this connection, it'should bestated that,in Fig. 4,-the locations ofthe particular'pull bars- 6I,"62,f63, 13,19 and I 18 'have ybeen diagrammat-loally vshown for VVillustrative purposes-in order1tosimplify the-drawing.

Each teletypevvriter has also been shown to be provided with a normally closed break contact connected in series with the locking-up circuit of the switching relays. rlhis is for the purpose of breakingf or discontinuing, a switching connection in response to the transmission and reception of a so-called break signal preceded by a figures signal. The figures signal causes the platen assembly E@ to be pulled forward into its upper case position by spring le. n moving forward, the platen assembly t@ pulls lever l'll forward sufficiently to remove slot E85! from the path of travel of extension lill oi pull bar HS.

Now, when a break signal is received by the connected teletypewriters, due to the momentary manual opening oi the break key 85 in any or^ the connected teletypewriters, their selecting mechanism l2 will effect the elevation of the break pull bar ilS by bail 'hl with the result that extension 85 of pull bar H5 engages with the le'it end of lever lig and raises it up. This elevates the left enel or" lever 32 and, consequently, lowers the right end of lever H32 thereby allowing spring 83 to pull down the left end or lever ii. As a result, the right end of lever itil is raised up and allows the normally closed. spring contact di to open.

However, this opening oi' contact 'i is only mcmentary because pull bar V58 is soon lowered by bail 'ill with the result that lever il@ is restored to normal condition by spring E85 thereby causing lever ll to be returned to its normal position. Nevertheless, the momentary opening of the break contact 5l is sumcient to open the locking-up circuit of all the switching relays which will, consequently, discontinue any of the switching connections that happen to be set uo at that time.

It is to be understood that this specific embodiment of the invention has been shown and described for purposes of explaining the principles and features of operation of the invention. Many changes may be made in the construction shown without departing from the scope of the invention. More switching contacts to be operated by other pull bars of the teletypewriters may be added whenever desired to perform any other functions that may be required. Likewise, the circuit connections of the various subscribers stations may be varied as desired to meet the requirements oi any particular communication system. 1t is also to be understood that the particular letter code combinations assigned for operating the switching contacts need not always be used as other letter code combinations may be employed by merely shifting the pull bar contacts from their present positions to positions over the tops of the pull bars corresponding to the desired letters. Consequently, the scope of the invention is to be limited only by the claims appended hereto.

What is claimed is:

l. A teletypewriter switching and transmission system including in combination a plurality of subscribers stations each having a teletypewriter and a transmitter-distributor, a transmission line for connecting the teletypewriters at the subscribers stations for the transmission oi permutation code combinations of signal impulses, switching means for stopping the transmitterdistributor at one station while starting the transmitter-distributor at another station, and instrumentalties for operating the switching means in response to the transmission of preassigned permutation code combinations of signa impulses over the system. 1

2. A teletypewrter switching system including in combination a plurality of subscribers stations each having a teletypewriter and a transmitterdistributor, a transmission line for connecting the teletypewriters at the subscribers stations for the transmission of permutation code combinations of significant current variations, switching means for stopping the transmitter-distributor at one station while starting the transmittervdistributor at another station, a plurality of contacts for controlling the operation oi the switching means, and operating means for selectively operating the contacts in response to the transmission over the system of certain preassigned permutation code combinations of signicant current variations.

3. A teletypewriter switching system including in combination a plurality of subscribers stations each having a teletypewriter with pull bars and a transmitter-distributor, a plurality of contacts mounted in each teletypewriter in operative relation with the pull bars, a transmission line for connecting the teletypewriters at the subscribers stations for the transmission of permutation code combinations of signicant current Variations, selecting mechanism in each teletypewriter for operating the pull bars in response to the transmission over the system of permutation code combinations of significant current variations, switching means for stopping the transmitterdistributor at one station while starting the transmitter-distributor at another station, and a circuit at each station connected in series with one of the contacts in each teletypewriter for controlling the energization of the switching means.

4. A teletypewrter system including in combination a plurality of subscribers stations each having a teletypewriter and a transmitter-distributor, a transmission line for connecting the teletypewriters at the subscribers stations for the transmission of permutation code combinations ol signal impulses, switching means for switching transmission from a transmitter-distributor at one station to a transmitter-distributor at another station, and control means for controlling the operation of the switching means.

to effect transmission from the transmitter-distributors in any desired sequence.

5. A teletypewriter system including in cornbination a plurality of subscribers stations each having a teletypewriter with a tape perforator and a transmitter-distributor, a common transmission line for interconnecting the teletypewriters at all the subscribers stations for the transmission of permutation code combinations perforated in the various tapes, switching means for switching transmission from a transmitterdistributor at one station to a transmitter-distributor at another station, and control means 'for controlling the operation of the switching means in accordance with signals perforated in the tape of each station as its transmitter-distributor transmits in its turn.

6. A teletypewriter system including in combination a plurality of subscribers stations each having a teletypewriter with a tape perforator and a transmitter-distributor, a common transmission line for interconnecting the teletypewriters at the subscribers stations with the transmitter-distributors for-the transmission of permutation code combinations perforated in each tape in succession, switching means for switching transmission from 'a transmitter-distributor at one station toa transmitter-'distributor at another'statiomand vcontrol means for controlling the operation ofv the switching means for determining which station shall have its transmitter-distributor started.

7. 'A teletypewriter switchingv system including in combination a plurality of subscribers stations each having a teletypewriter and `a. transmitter-distributor, a'transmission line for connecting the teletypewriters at the subscribers stations for the transmission of permutation code combinations .of signal impulses, control means at one of thesubscribers' stations for controlling the operation of the transmitter-distributor at that station, a normally Open energizing circuit for energizing saidcontrol means, va iirstinstrumentality forpreparing said Venergizing circuit in response to they transmission of a preassigned permutation code signal combination over the system, andasecon'd instrumentality'for completing said energizing circuit, in response-to` the transmission rof a different permutation code signal combination overthe system.

8. A teletypewriter switching system including in combination a plurality `of subscribersstations each having a teletypewriter, a main transmission line for connectingV the teletypewriters at the subscribers stat'ions'forthe transmission of Vsignal impulses, `one of said subscribers stations having an auxiliary teletypewriter, a subsidiary subscribers station having a teletypewriter, a subsidiary circuit for connecting the teletypewriter at the subsidiary subscribers station to said auxiliary teletypewriter, ,and in- I strumentalities at the station having'said auxiliary teletypewriter Vfor extending the 'main transmission line over the subsidiary circuitzto the teletypewriterat the subsidiarysubscribers station in response to preassigned signicantcurrent variations previously transmitted over said main transmission line.

9. A telegraph system including in corn-bination a plurality of subscribers stations eachjprovided with a printing telegraph instrument, 'a transmission channel for connecting said printing telegraph instruments, `starting means'for causing. the printing telegraph instrument at one subscribers station to transmit messages out over the transmission channel for recording bythe printing telegraph instruments'at the` otherl subscribers stations, instrumentalities forterminating transmission from this subscribers station and for switching theinitiation of the' transmission of messages from they subscribers station that is transmitting messages toA one of the subscribers stations that is recording the transmitted messages, and operating means for operatingsaid instrumentalities vin response to a preassigned operation of the printingtelegraph'instrument which is transmitting messagesat that time.

10. Ina telegraph system,`a transmission channel, `a subscribers station rconnected -into said transmission-channeland provided With-a printing telegraph Amachine `having printingrmechanism including pu-ll bars and also provided with a transmitter-distributorl vfor transmitting messages over the transmissionl channel, a start magnet for conditioning lsaid transmitter-distributor for operation, a control contactconnectedin parallel with'said start magnet, and means for openingzandlosing said control contact in response'to theoperationof Aa Mpreassigned `pull bar whereby the-eiectivenessofsaid start magnet lis controlled.

11. In a telegraph system, a transmission channel, la subscribers station connected into said transmission channel and provided with a printing telegraph machine lhaving printing mechanism and shift mechanism and also provided with a transmitter-distributor for transmitting messages over the transmission channel, a start magnet for conditioning said transmitter-distributor for operation, a shunt path connected in parallel with said start magnet, a plurality of controlfcontacts connected into said shunt path for opening and closing the shunt path whereby the startmagnet may be rendered ineffective, means for operating one of said contacts in responseto the operation of the shift mechanism, and means for operating another of saidy contacts in response to a preassigned operation of the printing mechanism.

12. `A telegraph system including in. combinai tion a transmission channel, a subscribers station -connected'in to the transmission channel, said subscribers station having transmitting meansy for transmitting messages over the transmission channel and printing mechanism including a platen assembly, a relay for controlling the operability of the transmitting means, energizing means for energizing the relay, a lockingup circuit for said relay, said locking-up circuit being divided into two parallel branches, a control contact connected into one branch of the locking-up circuit and another control contact connected. into the other branch of the lockingup circuit, means controlled by the platen assembly for operating one Contact, and means controlled-by another portion of the printing mechanism for operating the other contact whereby the locking-up circuit of the relay may be completely opened.

13. A teletypewriter system including in combination a plurality of of subscribers stations, a teletypewriter and transmitter-distributor at each station, a communication channel interconnecting said teletypewriters for the transmission of signals, switching means for establishing switching connections for startingv and stopping said transmitter-distributors in a predetermined sequence, 1a `break contact located in each teletypewriter connected into the conimumcation channel, Abreaking means foreiecting the operationof the break contact in all of the teletype- Writers connected into the system whereby any oi theswitchingconnections that happened to be set up ata particular time Aare discontinued.

14. Ina telety-pewriter switching system including in combination aplurality of subscribers stations-each having a teletypewriter and a tape perforator with a transmitter-distributor, anda communication channel for connecting said stations -forthe transmission and reception` of permutation `code ,combinations of significant current variations, the method of sequentialoperation of the transmitter-distributors Vwhich comprises perforating preassignedpermutationl code signals with one tape perforator, transmitting the signalsover the system, operating a device at one station in response to the transmission of certain of the signals overl the system to vstop one transmitter-distributor, and voperating another device at anotherstation in responseto the transmission of saidv certain signals over the system to start another'A transmitter-distributor for operation thereof.

15. y'A printing telegraph system comprising in combinationfa plurality` of subscribers stations each provided -with afprinting 'telegraph machine having at least one control contact, operating means for selectively operating the control contacts, a transmission channel for connecting the printing telegraph machines at the subscribers stations for the transmission of messages, starting means for causing the printing telegraph machine at one subscribers station to transmit messages out over the transmission channel for recording by the printing telegraph machines at the other subscribers stations, and instrumentalities for switching the initiation of the transmission of messages from the subscribers station that is transmitting messages to one of the subscribers stations that is recording the transmitted messages in response to the selective operation of at least one control contact at each of a plurality of the subscribers stations.

16. A printing telegraph system comprising in combination a plurality of subscribers stations each provided with a printing telegraph machine having at least one control contact, operating means for selectively operating the control contacts, a transmission channel for connecting the printing telegraph machines at the subscribers stations for the transmission of messages, starting means for causing the printing telegraph machine at one subscribers station to transmit messages out over the transmission channel for recording by the printing telegraph machines at the other subscribers stations, switching means for rotating the initiation of the transmission of messages from the subscribers station that is transmitting messages to one of the subscribers stations that is recording the transmitted messages only in a predetermined sequence in response to the selective operation of the control contacts.

17. A teletypewriter switching system including in combination a plurality of subscribers stations each having a teletypewriter, a main transmission line for connecting the teletypewriters at the subscribers stations for the transmission of signal impulses, one of said subscribers stations having its teletypewriter equipped with a control contact and also having an auxiliary teletypewriter, means for operating said control contact, a subsidiary subscribers station having a teletypewriter, a subsidiary circuit or connecting the teletypewriter at the subsidiary subscribers station to said auxiliary teletypewriter, an instrumentality located at the station having a teletypewriter equipped with a control contact for extending the main transmission line over the subsidiary circuit to the teletypewriter at the subsidiary subscribers station, operating means for operating said instrumentality, and means for controlling said operating means in accordance with the operation of said control contact.

18. A system comprising a plurality of permutation code storage transmitters associated at geographically separated points with a channel of telegraphic transmission, means operable from a station remote from a plurality of said points for sending upon said channel permutatively coded impulses, and selective means operable under the influence of said impulses according to the permutation thereof to initiate transmission selectively from one of said transmitters upon said channel.

19. A plurality of permutation code transmitters each controlled by a storage instrument for mechanical storage of code combinations, a channel of transmission associable with said transmitters, and means whereby code combinations terminate transmission upon said line from an `active source of transmission and selectively initiate transmission from one of said transmitters.

20. A permutation code switching and transmission system including in combination a plurality of stations each having a permutation code recording instrument and a telegraph transmitter, a transmission channel for connecting the transmitters at said stations for the transmission of permutation code combinations of signal impulses, switching means for stopping the transmitter at one station while starting the transmitter at another station, and instrumentalities for operating the switching means in response to the transmission of preassigned permutation code combinations of signal impulses over the system.

2l. A system including, in combination, a plurality of stations each having a permutation code recording instrument and an automatic telegraph transmitter, a transmission channel for connecting the transmitters at the stations for the transmission of permutation code combinations of signiiicant current variations, switching means for stopping the transmitter at one station, switching means for starting the transmitter at another station, permutatively controlled means for controlling the operation of both of said switching means, and operating means for selectively operating said permutatively controlled means in response to the transmission over the channel of certain preassigned permutation code combinations of signicant current variations.

22. A plurality of stations each having a transmitter of permutation code combinations and a receiving selector of permutation code combinations, a channel of transmission to which all of said transmitters may transmit and by which all of said receiving selectors may be actuated selectively, interconnections between certain of said selectors and associated transmitters whereby said selectors may be actuated to cause said transmitters to transmit one at a time in sequence.

23. A system of telegraphic permutation code transmission having two or more geographically separated stations each provided with elements capable of being selectively actuated. by permutation code and an emitter of permutatively coded electrical variations, and devices including at least one such said selector for substantially coincidently causing one emitter to begin emitting and another to cease emitting.

24. A system of telegraphic message transmission and distribution which comprises a telegraphic channel of transmission having stations operably associated therewith at separated places, each station being provided with a storage medium for storing telegraphic code combinations in physical form, a telegraphic transmitter controlled by said medium to transmit code combinations under the control of and in accordance with the combinations stored therein, and means associated with said stations for controlling remotely over said channel the initiation of transmission successively by a plurality of said transmitters.

25. A system of telegraphic message transmission and distribution which comprises a telegraphic channel of transmission, a plurality of automatic telegraph transmitters associable therewith to transmit thereover, a plurality of storage devices for storing variable sequences of telegraphic code combinations in physical form for controlling transmission from the respective ones of said transmitters, selective .means Vwhereby transmission may be selectively initiated from one of said transmitters, and means at a point remote from said one transmitter for controlling the selective operation ofsaid selective means over said channel.

26. A system of telegraphic message distribution having a plurality of automatic telegraph transmitters, each provided with a storagemedium for message code combinations to control the transmission thereof, means for storing code combinations representing separate messages independently in any one of said storage media with control combinations, a plurality of receiving stations, means for transmitting a particular one of said messages toV one of said stations and recording it thereat, and means adapted for selective operation under the control of said control code combinations for determining whether some other station also receives and records the same said. message.

27. The method of telegraphing which comprises supplying a series of automatic storage type telegraphic transmitters located remotely from each other with stored material fory transmission and causing the transmitters to transmit in sequence under control of the stored material automatically by interlockingcontrol.

28. The method of deriving messages froml a plurality of geographically separatedstorage devices each controlling a transmitter connected to a channel oi transmission Which comprises impressing upon the channel successive selective impulses and causing the transmitters to transmit successively under control of the impulses.

29. The method of telegraphic transmission which consists in supplying automatic transmitters connected to a channel of transmission with stored message material in physical form and causing b-y automatic control over said channel successive transmission by said transmitters.

`30. Thgmethcd of telegraphic control of a plurality of Widely separated transmitters which comprises automatically and successively by remote control over achannel of telegraphic transmission causing each'of the transmitters in turn to transmit over said channel telegraphic code combinations and controlling the beginning of transmissionfrom one transmitter as an incident to and substantially simultaneously With the termination of transmission from another.

31. A plurality of ltelegraph transmitters associable with a channel of telegraphic transmission and means remotely controllable over said channel of transmission to initiate and terminate successive transmission upon said channel by said transmitters.

32. A plurality of telegraph transmitters associable with a channel of telegraphic transmission, storage means suppliable with permutation codes in physical form for a plurality of said transmitters and individual-thereto, and means remotely controllable over said channel of transmission by selected stored permutation codes to initiate and terminate successive Ytransmission upon said channel by said transmitters.

ancetre f33. Apermutation vcode :system having a stat-ioninc1udingA a tape vcontrolled transmitter for transmitting-code Acon'ibinations according to the storage .of its1tape,:means;for emitting permutation code combinations fromaipoint remote from said':station,and Imeans at'said station operable independent of'the storage of Ysaid tape, .selectively :effective undertheLcontrol of said lastnamed'code comb-inationsaccording to the permutation,thereof'toV change said transmitter from anon-transmittingto a transmitting condition. 34.:A system comprisingaplurality or" permutation; code .storageV transmitters associated with a -channel of telegraphic transmission, means operable ironia remoteV station for sending permutatively; codedV impulses, and vselective means operableunderzthe influence of said impulses according rto the-permutation thereof 'to initiate transmissionseleotively from one of said transmittersxupongsaid,channel, said selective moans being-operable independently of the storage of the:devicefromtwhich transmission is initiated. `35. nicombination, a channel of telegraphic transmission, more than one transmitter of telegraphic impulses ,having controlling contacts Whichiare capable-of controlling impulse transmission poversaid channel, said transmitters being geographically separated, selective means associated with said channel, and interconnections between said seleetivetmeans and said, transmitters whereby suitably -chosen combinations of impulsesupon said channel actuate said selective means and through said interconnections initiate transmissionA upon said channel from Aone of said transmitters .at a time.

36. lncombination, a channel of telegraphic transmission, more than one transmitter of telegraphic impulses controlling contacts which are capable of, impulse transmission over` said channelfselective vmeans associated with said chanel=and1interconnections between said selective means and said'transmitterswhereby suitably chosenp'combinations of impulses upon said channelfactuate said selective means and through said `interconnections automatically initiate transmissionupon said channel from one of said transmitters at a time.

3W. Ag permutation code transmission system having permutation code transmitter means operably related to a channel' of transmission, mechanical codestorage means. for Asupplying codes to be transmitted by said transmitter, other permutation code transmitter means operably related tojsaid'channel ofv transmission, other mechanical codestorage means for supplying codes to betransmitted bysaid other permutation code transmitter.means, said transmitter means being located geographically remote from said other transmitter means, and means whereby permutated code impulses impressed upon said channel byone of said means initiates transmitting operation-:by another thereof.

HARRY R. STARR. WALTER'E. WADDINGTON. 

